Blasts that produce gamma-ray bursts may exceed the speed of light

A new model of gamma ray bursts suggests the blasts that trigger the cosmic phenomena may travel faster than the speed of light within surrounding gas clouds. The creators of the new model, astrophysicists Jon Hakkila of the College of Charleston and Robert Nemiroff of the Michigan Technological University, claim these superluminal jets don't violate Einstein's theory of relativity. Scientists have previously identified time-reversibility properties in the light curves generated by gamma ray bursts, which are energetic explosions astronomers have observed in distant galaxies. According to Hakkila and Nemiroff, superluminal jets could help explain this time-reversibility. Because the new model posits that the jets only move faster than light does through the jet medium, not through vacuum, Hakkila and Nemiroff claim it doesn't contradict Einstein's theory of relativity. According to the two astrophysicists, the new model, detailed this week in the Astrophysical Journal, can "account for a variety of unexplained yet observed GRB pulse behaviors." Specifically, the collisional radiation and shockwaves produced by superluminal jets as they're speeding up or slowing down can account for a variety of patterns observed on GRB light curves. "These transitions create both a time-forward and a time-reversed set of light-curve features through the process of relativistic image doubling," researchers wrote in their paper. In other words, whether time is moving forward or backward, the features in the gamma ray burst light curve behave the same way.

The new model, according to the paper's authors, is the first to account for this phenomenon.

"Standard gamma-ray burst models have neglected time-reversible light curve properties," Hakkila said in a news release. "Superluminal jet motion accounts for these properties while retaining a great many standard model features."